Oligomeric hydroxy arylether phthalonitiles and synthesis thereof

ABSTRACT

An aromatic ether oligomer or polyaromatic ether comprising the formula: 
                 
 
wherein Ar is an independently selected divalent aromatic radical; formed by reacting a dihydroxyaromatic with a dihaloaromatic; and wherein the reaction is performed in the presence of a copper compound and cesium carbonate. The polyaromatic ether is formed when neither the dihydroxyaromatic nor the dihaloaromatic is present in an excess amount. The aromatic ether oligomer is formed by using an excess of either dihydroxyaromatic or dihaloaromatic. A phthalonitrile monomer comprising the formula: 
                 
 
formed by reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer. A thermoset formed by curing the phthalonitrile monomer. Processes for forming all the above.

This application is a divisional application of U.S. patent applicationSer. No. 10/135,012 filed on Apr. 26, 2002 now U.S. Pat. No. 6,756,470.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to polyaromatic ethers, aromatic ether oligomers,phthalonitrile monomers containing aromatic ether oligomer spacers,thermosets made from such phthalonitrile monomers, and processes formaking the same.

2. Description of the Prior Art

Phthalonitrile monomers and phthalonitrile polymers of various types aredescribed generally in U.S. Pat. Nos. 3,730,946, 3,763,210, 3,787,475,3,869,499, 3,972,902, 4,209,458, 4,223,123, 4,226,801, 4,234,712,4,238,601, 4,259,471, 4,304,896, 4,307,035, 4,315,093, 4,351,776,4,408,035, 4,409,382, 4,410,676, 5,003,039, 5,003,078, 5,004,801,5,132,396, 5,159,054, 5,202,414, 5,208,318, 5,237,045, 5,242,755,5,247,060, 5,292,854, 5,304,625, 5,350,828, 5,352,760, 5,389,441,5,464,926, 5,925,475, 5,965,268, 6,001,926, and U.S. Pat. No. 6,297,298,all incorporated herein by reference.

The above references generally teach methods for making and polymerizingphthalonitrile monomers. Such monomers typically have two phthalonitrilegroups, one at each end of a connecting spacer chain. The monomers canbe cured, whereby the cross-linking occurs between cyano groups. Thesecross-linked networks typically have high thermal and oxidativestability.

Phthalonitrile monomers with aromatic ether oligomeric or polymericspacers are expected to be useful because they are predicted to have lowmelting points. Phthalonitrile monomers with a large window between themelting point and the cure temperature are desirable to control the rateof curing and the viscosity during curing.

U.S. Pat. No. 4,259,471 to Keller et al. discloses a phthalonitrilemonomer having a polyphenoxy spacer with from 1 to 10 phenyl groups inthe spacer chain. The monomer is made by reacting 4-nitrophthalonitrilewith an aromatic diol. The aromatic diol is a phenoxy chain withterminal hydroxy groups. The patent states that the aromatic diol can bemade by an Ullmann synthesis. However, the patent does not teach how tomake the aromatic diol with more than two phenylene groups. It is knownin the prior art that an Ullmann synthesis can be used to create asingle aromatic ether linkage by reacting a haloaromatic with ahydroxyaromatic in the presence of a stoichiometric amount of a coppercomplex. There are no known prior reports of the use of an Ullmannsynthesis to make an oligomeric or polymeric aromatic ether containingthree or more aromatic groups.

U.S. Pat. No. 6,297,298 to Keller et al. recites a phthalonitrilemonomer having a polyphenoxy spacer as an embodiment of a generalstructure. The patent does not disclose any examples of or a process formaking this phthalonitrile monomer.

The compound m-bis[m-(m-phenoxyphenoxy)phenoxy]benzene is a commerciallyavailable aromatic ether oligomer. There are no other known priorreports of other aromatic ether oligomers.

Marcoux et al., J. Am. Chem. Soc. 1997, 119, 10539, discloses a methodfor synthesizing a diaryl ether from a haloaromatic and a phenol using acatalytic amount of a copper complex and cesium carbonate. This methoddoes not require the harsh conditions of an Ullmann synthesis such ashigh temperatures. The method also avoids the use of a stoichiometricamount of copper. The publication does not disclose any use of themethod to make an aromatic ether oligomer.

There is need for process to make an aromatic ether oligomer and apolyaromatic ether. The resulting aromatic ether oligomer can then bereacted with a nitrophthalonitrile to make a phthalonitrile monomer. Thephthalonitrile monomer can then be cured to form a thermoset.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a polyaromatic ether and anaromatic ether oligomer.

It is a further object of the invention to provide a phthalonitrilemonomer with an aromatic ether oligomer spacer.

It is a further object of the invention to provide a thermoset made bycuring a phthalonitrile monomer with an aromatic ether oligomer spacer.

These and other objects of the invention are accomplished by process ofpreparing a polyaromatic ether comprising the formula:

wherein Ar is an independently selected divalent aromatic radical,comprising the step of reacting a dihydroxyaromatic with adihaloaromatic; wherein neither the dihydroxyaromatic nor thedihaloaromatic is present in an excess amount; and wherein the reactionis performed in the presence of a copper compound and cesium carbonate.

The invention further comprises a process of preparing the abovepolyaromatic ether comprising the step of reacting a halohydoxyaromaticin the presence of a copper compound and cesium carbonate.

The invention further comprises a process of preparing an aromatic etheroligomer comprising the formula:

wherein Ar is an independently selected divalent aromatic radical;wherein T is a terminating group independently selected from the groupconsisting of —OH and —X; wherein X is independently selected from thegroup consisting of Br and I; and wherein n is an integer greater thanor equal to 1; comprising the step of reacting a dihydroxyaromatic witha dihaloaromatic; wherein the reaction is performed in the presence of acopper compound and cesium carbonate; and wherein either thedihydroxyaromatic or the dihaloaromatic is present in an excess amount.

The invention further comprises a process of preparing a phthalonitrilemonomer comprising the formula:

wherein Ar is an independently selected divalent aromatic radical; andwherein n is an even integer greater than or equal to 2; comprising thestep of reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminatedaromatic ether oligomer.

The invention further comprises a process of preparing a thermosetcomprising the step of curing a mixture comprising the abovephthalonitrile monomer.

The invention further comprises the polyaromatic ether, aromatic etheroligomer, phthalonitrile monomer, and thermoset described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The synthesis of the thermoset is performed in three steps. First, adihydroxyaromatic is reacted with a dihaloaromatic to form an aromaticether oligomer. Second, the aromatic ether oligomer is reacted with a 3-or 4-nitrophthalonitrile to make a phthalonitrile monomer. Third, thephthalonitrile monomer is cured to make a thermoset. Any reference to aningredient can refer to one embodiment of such ingredient or acombination of one or more embodiments. All polymeric and oligomericstructures claimed include all configurations, isomers, and tacticitiesof the polymers and oligomers within the scope of the claims. The term“oligomer” as used herein does not place any upper or lower limit on thechain length of the oligomer.

1. Formation of the Aromatic Ether Oligomer

In the first step the dihydroxyaromatic is reacted with thedihaloaromatic to form the polyaromatic ether or the aromatic etheroligomer as shown in formula 1.

The halo groups, X, on the dihaloaromatic can be iodo or bromo or acombination thereof. Each Ar is an independently selected divalentaromatic radical. The divalent aromatic radical can be any divalentradical with or without substituents containing one or more fusedaromatic rings, one or more non-fused aromatic rings with or withoutintervening functional groups, or combinations thereof wherein theradical sites are on the same or different aromatic rings. 1,3-Phenyleneand 1,4-phenylene are typical divalent aromatic radicals. The divalentaromatic radical can be different in each reactant. The divalentaromatic radical can also be different in multiple embodiments of thesame reactant. For example, the dihydroxyaromatic can comprise acombination of any of resorcinol (m-dihydroxybenzene), hydroquinone(p-dihydroxybenzene), and any other dihydroxyaromatics. By furtherexample, the dihaloaromatic can comprise a combination of any ofm-dibromobenzene, p-dibromobenzene, m-diiodobenzene, p-diiodobenzene,m-bromoiodobenzene, p-bromoiodobenzene, and an other dihaloaromatics.

The aromatic ether oligomer or the polyaromatic ether has a structurethat alternates between an aromatic ether functional group containing adivalent aromatic radical from the dihydroxyaromatic and an aromaticether functional group containing a divalent aromatic radical from thedihaloaromatic.

In one embodiment neither the dihydroxyaromatic nor the dihaloaromaticis present in an excess amount, and the product is a polyaromatic ether.The polyaromatic ether can have a high molecular weight. Typically n isgreater than or equal to 7. The polyaromatic ether is not necessarilyconvertible to a phthalonitrile monomer, but can be useful in otherapplications. Formula 2 shows the formation of a polyaromatic ether froma 1:1 molar ratio of hydroquinone and p-diiodobenzene. In anotherembodiment the polyaromatic ether is formed from a halohydroxyaromatic.Formula 3 shows the formation of a polyaromatic ether from 4-iodophenol.

In another embodiment, either the dihydroxyaromatic or thedihaloaromatic is present in an excess amount to form an aromatic etheroligomer. This is shown in formula 4.

The term n is an integer greater than or equal to 1. Typically, n isless than or equal to 100. More typically, n is equal to 2, 4, 6, or 8.T represents a terminating group. The terminating groups areindependently selected from the group consisting of —OH or —X. In someembodiments, the same kind of terminating group is on both ends of thearomatic ether oligomer, although different embodiments of that kind maybe found when the terminating group is —X. For example, when thedihaloaromatic is present in an excess amount and is1-bromo-4-iodobenzene, both terminating groups can be —X, wherein any —Xcan be either —Br or —I. The process for making the aromatic etheroligomer with each terminating group is discussed separately.

When both terminating groups are —OH, the aromatic ether oligomer is ahydroxy-terminated aromatic ether oligomer. In this case, n is an eveninteger greater than or equal to 2. The hydroxy groups are bonded to thedivalent aromatic radical from the dihydroxyaromatic. This structure isformed when the dihydroxyaromatic is present in an excess amount. Whenall the dihaloaromatic is consumed, there is still dihydroxyaromaticavailable to terminate the aromatic ether oligomer. Typically there issufficient dihydroxyaromatic present to terminate both ends of allaromatic ether oligomeric molecules. If not, in some molecules oneterminating group is —OH and the other is —X. Formula 5 shows thegeneral reaction scheme and formula 6 shows the reaction of a 2:1 molarratio of resorcinol and p-diiodobenzene. Formula 7 shows the reaction ofa 2:1 molar ratio of resorcinol and 4,4′-diiodobiphenyl.

The product in formula 6 represents the average length of the chain. Theaverage length has three units, which corresponds to n=2. There may alsobe longer chain lengths present as well as unreacted resorcinol. Formula7 illustrates a divalent aromatic radical with two non-fused aromaticrings. There can also be intervening functional groups between thearomatic rings, such as in bis(4-iodophenyl)methylene.

Formula 8 shows an example using a 3:2 ratio. The dihydroxyaromatic isresorcinol and the dihaloaromatic is a 1:1 molar combination ofm-diiodobenzene and p-dibromobenzene. The average chain has fivearomatic groups, which corresponds to n=4. Other configurations of them-phenylene and p-phenylene groups from the dihaloaromatics can also bepresent as well as molecules with only m-phenylene or only p-phenylenegroups from the dihaloaromatics. More than one dihydroxyaromatic canalso be used either with a single dihaloaromatic or with more than onedihaloaromatic. Formula 8 shows a 1:1 molar ratio of twodihaloaromatics, however the molar ratios of more than onedihydroxyaromatics or dihaloaromatics can be any desired ratios.

When both terminating groups are —X, the aromatic ether oligomer is ahalo-terminated aromatic ether oligomer. In this case, n is an eveninteger greater than or equal to 2. The halo groups are bonded to thedivalent aromatic radical from the dihaloaromatic. The halo-terminatedaromatic ether oligomer is made when the dihaloaromatic is present in anexcess amount. When all the dihydroxyaromatic is consumed, there isstill dihaloaromatic available to terminate the aromatic ether oligomer.Typically there is sufficient dihaloaromatic present to terminate bothends of all aromatic ether oligomer molecules. If not, in some moleculesone terminating group is —OH and the other is —X. The same variations ofhalo-terminated aromatic ether oligomers are possible as forhydroxy-terminated aromatic ether oligomers. Formula 9 shows the generalreaction scheme. A 2:1 molar ratio of m-diiodobenzene and hydroquinonewould react as in formula 10. The average chain has three aromaticgroups, which corresponds to n=2.

A second way to make a hydroxy-terminated aromatic ether oligomer is toreact a halo-terminated aromatic ether oligomer with adihydroxyaromatic. This dihydroxyaromatic can be the same or differentfrom that used to make the halo-terminated aromatic ether oligomer. Thisprocess can be useful for making a hydroxy-terminated aromatic etheroligomer where the aromatic groups at the ends of the chain aredifferent from those in the middle. The dihydroxyaromatic used in thisstep can also be a combination of dihydroxyaromatics. Formula 11 showsthe general reaction scheme. Ar″ is an independently selected divalentaromatic radical. Formula 12 shows the reaction of the product offormula 10 with 1,4-naphthalenediol. 1,4-naphthalenediol is an exampleof a dihydroxyaromatic having a divalent aromatic radical having twofused aromatic rings.

A similar process can be used to form an aryl-terminated aromatic etheroligomer. This aromatic ether oligomer is made by reacting ahydroxy-terminated aromatic ether oligomer with a haloaromatic. Thehaloaromatic is a monovalent aromatic radical with either a bromo oriodo substituent. The monovalent aromatic radical can be any monovalentradical with or without substituents containing one or more fusedaromatic rings, one or more non-fused aromatic rings with or withoutintervening functional groups, or combinations thereof wherein theradical site is on an aromatic ring. Phenyl is a typical monovalentaromatic radical. Typically, there is only one halo substituent. Thehaloaromatic can be a combination of haloaromatics. The haloaromaticreacts with the terminal hydroxide groups of the hydroxy-terminatedaromatic ether oligomer to produce the aryl-terminated aromatic etheroligomer. Formula 13 shows the general reaction scheme. Formula 14 showsthe reaction of the product of formula 6 with iodobenzene.

The aryl-terminated aromatic ether oligomer can also be formed byreacting a halo-terminated aromatic ether oligomer with ahydroxyaromatic. The hydroxyaromatic is a monovalent aromatic radicalwith a hydroxy substituent. The same variations are possible asdescribed in the previous paragraph.

All of the above reactions are performed in the presence of a coppercompound and cesium carbonate. Typically the copper compound is CuI orCuBr. Other suitable copper compounds include, but are not limited to,CuCl, CuBr₂, and CuSO₄. Typically, the dihydroxyaromatic,dihaloaromatic, copper compound, and cesium carbonate are dissolved insolvent and heated. Typically, after the reaction is complete thearomatic ether oligomer can then be precipitated with an aqueous acidicsolution. The average molecular weight of the aromatic ether oligomer orthe polyaromatic ether is controlled by the ratio of the reactants asdescribed above.

The hydroxy-terminated aromatic ether oligomers can be used to make thephthalonitrile monomers described below, as well as numerous newpolymers and compounds through the reaction of the hydroxyl group.

2. Formation of the Phthalonitrile Monomer

In the second step, the hydroxy-terminated aromatic ether oligomer isreacted with 3- or 4-nitrophthalonitrile to make the phthalonitrilemonomer. Neither a halo-terminated aromatic ether oligomer nor anaryl-terminated aromatic ether oligomer can be used in this step.Formula 15 shows the general reaction scheme. Formula 16 shows thereaction of the product of formula 6 with 4-nitrophthalonitrile.

Typically, there is at least a 2:1 molar ratio of 3- or4-nitrophthalonitrile to hydroxy-terminated aromatic ether oligomer toensure that all terminal hydroxide groups react with the 3- or4-nitrophthalonitrile. Any remaining unreacted terminal hydroxide groupscan make it more difficult to control the reaction during the curingstep. Typically, the hydroxy-terminated aromatic ether oligomer and the3- or 4-nitrophthalonitrile are dissolved in a solvent and heated in thepresence of a base.

The previous step of forming the hydroxy-terminated aromatic etheroligomer typically produces a combination of multiple hydroxy-terminatedaromatic ether oligomers (including unreacted dihydroxyaromatic) havingan average value of n. This combination can be reacted with the 3- or4-nitrophthalonitrile to form a combination of phthalonitrile monomershaving different values of n. This can result in some phthalonitrilemonomers where n is zero.

3. Formation of the Thermoset.

In the final step, a mixture comprising the phthalonitrile monomer iscured to form the thermoset. The cyano groups are the cure sites. Asthese groups react with each other a cross-linked thermoset is formed.The mixture can comprise multiple phthalonitrile monomers havingdifferent values of n. Such a mixture is produced when thephthalonitrile monomers are produced from a combination ofhydroxy-terminated aromatic ether oligomers having an average value ofn.

The mixture can also comprise 4,4′-bis(3,4-dicyanophenoxy)biphenyl,bis[4-(3,4-dicyanophenoxy)phenyl]dimethylmethane,bis[4-(2,3-dicyanophenoxy)phenyl]dimethylmethane,bis[4-(3,4-dicyanophenoxy)phenyl]-bis(trifluoromethyl)methane,bis[4-(2,3-dicyanophenoxy)phenyl]-bis(trifluoromethyl)methane,1,3-bis(3,4-dicyanophenoxy)benzene, or1,4-bis(3,4-dicyanophenoxy)benzene. These compounds are alsophthalonitrile monomers. The mixture can also comprise any compound withone or more phthalonitrile groups. Typically, these phthalonitrilecompounds have two or more phthalonitrile groups. Such phthalonitrilecompounds include, but are not limited to, the phthalonitrile monomersdisclosed in the patents cited above. All these compounds can cure withthe phthalonitrile monomers of the present invention.

Typically the mixture comprises a curing agent. The curing agent can beany substance useful in promoting the polymerization of thephthalonitrile monomer. More than one curing agent can be used.Typically, the same amount of curing agent can be used as conventionallyused in curing analogous prior art monomers. Typically the curing agentis added to a melt of the phthalonitrile monomer with stirring. Themixture is then cured in one or more curing stages. Typical curingtemperatures range from about 80° C. to about 500° C. More typically,the range is from 80° C. to about 375° C. Generally, more completecuring occurs at higher temperatures.

Suitable curing agents include, but are not limited to, aromatic amines,primary amines, secondary amines, diamines, polyamines,amine-substituted phosphazenes, phenols, strong acids, organic acids,strong organic acids, inorganic acids, metals, metallic salts, metallicsalt hydrates, metallic compounds, halogen-containing aromatic amines,clays, and chemically modified clays. The use of clays or chemicallymodified clays may improve the mechanical and flammability properties ofthe thermoset. Typically, chemical modification of a clay involvesreplacing sodium ions with ammonium to form quarternary ammonium salts.

Specific curing agents include, but are not limited to,bis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS),bis[4-(3-aminophenoxy)phenyl]sulfone (m-BAPS),1,4-bis(3-aminophenoxy)benzene (p-APB), 1,12-diaminododecane,diphenylamine, epoxy amine hardener, 1,6-hexanediamine,1,3-phenylenediamine, 1,4-phenylenediamine, p-toluenesulfonic acid.cuprous iodide, cuprous bromide, 1,3-bis(3-aminophenoxy)benzene (m-APB),3,3′-dimethyl4,4′-diaminodiphenylsulfone,3,3′-diethoxy-4,4′-diaminodiphenylsulfone,3,3′-dicarboxy-4,4′-diaminodiphenylsulfone,3,3′-dihydroxy-4,4′-diaminodiphenylsulfone,3,3′-disulfo-4,4′-diaminodiphenylsulfone, 3,3′-diarminobenzophenone,4,4′-diaminobenzophenone, 3,3′-dimethyl-4,4′-diaminobenzophenone,3,3′-dimethoxy-4,4′-diaminobenzophenone,3,3′-dicarboxy-4,4′-diaminobenzophenone,3,3′-dihydroxy-4,4′-diaminobenzophenone,3,3′-disulfo4,4′-diaminobenzophenone, 4,4′-diaminodiphenyl ethylphosphine oxide, 4,4′-diaminodiphenyl phenyl phosphine oxide,bis(3-aminophenoxy-4′-phenyl)phenyl phosphine oxide, methylenedianiline, hexakis(4-aminophenoxy)cyclotriphosphazene,3,3′-dichloro-4,4′-diaminodiphenylsulfone,2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl,2,2′-bis(4-aminophenyl)hexafluoropropane,bis[4-(4-aminophenoxy)phenyl]2,2′-hexafluoropropane,1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane,3,3′-dichloro-4,4′-diaminobenzophenone,3,3′-dibromo-4,4′-diaminobenzophenone, aniline-2-sulfonic acid,8-aniline-1-naphthalenesulfonic acid, benzene sulfonic acid,butylsulfonic acid, 10-camphorsulfonic acid, 2,5-diaminobenzenesulfonicacid, 6-dimethylamino-4-hydroxy-2-naphthalenesulfonic acid,5-dimethylamino-1-naphthalenesulfonic acid,4-hydroxy-3-nitroso-1-naphthalenesulfonic acid tetrahydrate,8-hydroxyquinoline-5-sulfonic acid, methylsulfonic acid, phenylboricacid, 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid, 1,5-naphthalenedisulfonic acid, 2,6-naphthalenedisulfonic acid,2,7-naphthalenedisulfonic acid, picrylsulfonic acid hydrate,2-pyridineethanesulfonic acid, 4-pyridineethanesulfonic acid,3-pyridinesulfonic acid, 2-pyridinylhydroxymethanesulfonic acid,sulfanilic acid, 2-sulfobenzoic acid hydrate, 5-sulfosalicylic acidhydrate, 2,4-xylenesulfonic acid, sulfonic acid containing dyes, organicphosphorus-containing acids, phenylphosphinic acid, diphenylphosphinicacid, propylphosphonic acid, 1-aminoethylphosphonic acid,4-aminophenylphosponic acid, butylphosphonic acid, t-butylphosphonicacid, 2-carboxyethylphosphonic acid, 2-chloroethylphosphonic acid,dimethylphosphonic acid, ethylphosphonic acid, methylenediphosphonicacid, methylphosphonic acid, phosphonoacetic acid, bis(hydroxymethyl)phosphonic acid, chloromethylphosphonic acid, di-n-butylphosphonic acid,dichloromethylphosphonic acid, diphenyldithiophosphonic acid,1,2-ethylenediphosphonic acid, n-hystaderylphosphonic acid,hydroxymethylphosphonic acid, n-octadecylphosphonic acid,n-octylphosphonic acid, phenylphosphonic acid, propylenediphosphonicacid; n-tetradecylphosphonic acid, concentrated sulfuric acid,phenylphosphonic acid, copper, iron, zinc, nickel, chromium, molybdenum,vanadium, beryllium, silver, mercury, tin, lead, antimony, calcium,barium, manganese, magnesium, cobalt, palladium, platinum, stannouschloride, cuprous bromide, cuprous cyanide, cuprous ferricyanide, zincchloride, zinc bromide, zinc iodide, zinc cyanide, zinc ferrocyanide,zinc acetate, zinc sulfide, silver chloride, ferrous chloride ferricchloride, ferrous ferricyanide, ferrous chloroplatinate, ferrousfluoride, ferrous sulfate, cobaltous chloride, cobaltic sulfate,cobaltous cyanide, nickel chloride, nickel cyanide, nickel sulfate,nickel carbonate, stannic chloride, stannous chloride hydrates, stannouschloride dihydrate, aluminum nitrate hydrates, aluminum nitratenonahydrate, triphenylphosphine oxide complex, montmorillonite, andchemically modified montmorillonite.

The invention has the advantage of using a low melting phthalonitrilemonomer. As the value of n increases, the processing temperature of thephthalonitrile monomer is shifted to lower temperatures. The low meltingpoint allows the monomer to have a lower viscosity at a giventemperature than other phthalonitrile monomers. A low viscosity resinenables composite processing by resin transfer molding, resin infusionmethods, and filament winding, without heating the curing mixture to atemperature that initiates curing. Curing can be initiated when themixture is in position and need not flow any further. Furthermore, a lowmelt viscosity and a larger processing window are useful for fabricationof thick composite sections where the melt must impregnate thick fiberpreforms. The curing mixture viscosity is a function of both the curingagent concentration and the melt temperature. Thus, low meltingphthalonitrile monomers and curing agents that do not volatilize atelevated cure temperatures can enhance the processability ofphthalonitrile-based composites. This is important since most hightemperature resins are not amenable to processing by cost effectivemethods such as resin transfer molding, resin infusion molding, filamentwinding, and oven cure due to high initial viscosities, the evolution ofvolatiles during the cure, and solvent-related problems.

The thermoset has the advantage of very desirable thermo-oxidativeproperties, which may be unaffected by the nature of the curing agent.The thermoset also has improved physical properties, such as toughnessand processability, relative to systems with a short spacer between theterminal phthalonitrile moieties. Generally, toughness and brittlenessare improved with lower cross-link densities. This can be achieved byusing phthalonitrile monomers with longer spacer chains.

Having described the invention, the following examples are given toillustrate specific applications of the invention. These specificexamples are not intended to limit the scope of the invention describedin this application.

A. Synthesis of Aromatic Ether Oligomer

EXAMPLE 1

Synthesis of hydroxy-terminated aromatic ether oligomer (n=2) fromresorcinol and m-diiodobenzene with copper (I) iodide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 2.2 g (20.0 mmol)of resorcinol, 3.3 g (10.0 mmol) of m-diiodobenzene, 6.5 g (20.0 mmol)of cesium carbonate, 0.1 g (0.5 mmol) copper (I) iodide, 13 mL ofN,N-dimethylformamide (DMF), 7 mL of toluene, and 0.1 mL of ethylacetate. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 126-127° C. under argon for 23 hours. Duringthis time, water formed as a byproduct was removed from the reactionmixture by azeotropic distillation. The progress of the reaction wasmonitored by FTIR spectroscopy. When complete conversion to thehydroxy-terminated aromatic ether oligomer was indicated by FTIR,refluxing was stopped and toluene was removed from the reaction mixtureby distillation. When the temperature of the reaction mixture reached150° C., it was assumed that all the toluene had been removed. Thereaction mixture was then cooled to room temperature. After cooling, themixture was poured into 5% sodium hydroxide and extracted 5 times withdiethyl ether to remove residual solvents. The aqueous layer was madeacidic with concentrated hydrochloric acid. The solid precipitate thatformed was extracted by washing 3 times with diethyl ether. The etherextracts were separated, dried over sodium sulfate, filtered, andsolvent was removed by vacuum under ambient conditions. The vacuum driedhydroxy-terminated aromatic ether oligomer weighed 3.0 g (100%).

EXAMPLE 2

Synthesis of hydroxy-terminated aromatic ether oligomer (n=4) fromresorcinol and m-diiodobenzene with copper (I) iodide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 3.3 g (30.0 mmol)of resorcinol, 6.6 g (20.0 mmol) of m-diiodobenzene, 9.8 g (30.0 mmol)of cesium carbonate, 0.2 g (1.0 mmol) copper (I) iodide, 13 mL ofN,N-dimethylformamide (DMF), 7 mL of toluene, and 0.1 mL of ethylacetate. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 126-127° C. under argon for 26 hours. Duringthis time, water formed as a byproduct was removed from the reactionmixture by azeotropic distillation. The progress of the reaction wasmonitored by FTIR spectroscopy. When complete conversion to thehydroxy-terminated aromatic ether oligomer was indicated by FTIR,refluxing was stopped and toluene was removed from the reaction mixtureby distillation. When the temperature of the reaction mixture reached150° C., it was assumed that all the toluene had been removed. Thereaction mixture was then cooled to room temperature. After cooling, themixture was poured into 5% sodium hydroxide and extracted 5 times withdiethyl ether to remove residual solvents. The aqueous layer was madeacidic with concentrated hydrochloric acid. The solid precipitate thatformed was extracted by washing 3 times with diethyl ether. The etherextracts were separated, dried over sodium sulfate, filtered, andsolvent was removed by vacuum under ambient conditions. The vacuum driedhydroxy-terminated aromatic ether oligomer weighed 3.3 g (69%).

EXAMPLE 3

Synthesis of hydroxy-terminated aromatic ether oligomer (n=8) fromresorcinol and m-diiodobenzene with copper (I) iodide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 2.2 g (20.0 mmol)of resorcinol, 5.3 g (16.0 mmol) of m-diiodobenzene, 6.5 g (20.0 mmol)of cesium carbonate, 0.2 g (0.8 mmol) copper (I) iodide, 13 mL ofN,N-dimethylformamide (DMF), 5 mL of toluene, and 0.1 mL of ethylacetate. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 130-131° C. under argon for 19 hours. Duringthis time, water formed as a byproduct was removed from the reactionmixture by azeotropic distillation. The progress of the reaction wasmonitored by FTIR spectroscopy. When complete conversion to thehydroxy-terminated aromatic ether oligomer was indicated by FTIR,refluxing was stopped and toluene was removed from the reaction mixtureby distillation. When the temperature of the reaction mixture reached150° C., it was assumed that all the toluene had been removed. Thereaction mixture was then cooled to room temperature. After cooling, themixture was poured into 5% sodium hydroxide and extracted 5 times withdiethyl ether to remove residual solvents. The aqueous layer was madeacidic with concentrated hydrochloric acid. The solid precipitate thatformed was extracted by washing 3 times with diethyl ether. The etherextracts were separated, dried over sodium sulfate, filtered, andsolvent was removed by vacuum under ambient conditions. The vacuum driedhydroxy-terminated aromatic ether oligomer weighed 2.0 g (59%).

EXAMPLE 4

Synthesis of hydroxy-terminated aromatic ether oligomer (n=2) fromresorcinol and m-dibromobenzene with copper (I) iodide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 1.1 g (10.0 mmol)of resorcinol, 1.2 g (5.0 mmol) of m-dibromobenzene, 0.05 g (0.25 mmol)copper (I) iodide, 20 mL of N,N-dimethylformamide (DMF) and 10 mL oftoluene. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 130-131° C. ° C. under argon for 6 hours. Duringthe first several hours of reflux, 8.2 g (25.0 mmol) of pulverizedcesium carbonate was added in four portions and water formed as abyproduct was removed from the reaction mixture by azeotropicdistillation. The progress of the reaction was monitored by FTIRspectroscopy. When complete conversion to the hydroxy-terminatedaromatic ether oligomer was indicated by FTIR, refluxing was stopped andtoluene was removed from the reaction mixture by distillation. When thetemperature of the reaction mixture reached 150° C., it was assumed thatall the toluene had been removed. The reaction mixture was then cooledto room temperature. After cooling, the reaction mixture was poured into5% sodium hydroxide and the solution was filtered to remove residualcopper (I) iodide. The solution was then made acidic with concentratedhydrochloric acid. The solid precipitate that formed was extracted bywashing 3 times with diethyl ether. The ether extracts were separated,dried over sodium sulfate, filtered, and solvent was removed by vacuumunder ambient conditions. The vacuum dried hydroxy-terminated aromaticether oligomer weighed 1.4 g (93%).

EXAMPLE 5

Synthesis of hydroxy-terminated aromatic ether oligomer (n=2) fromresorcinol and p-dibromobenzene with copper (I) iodide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 1.1 g (10.0 mmol)of resorcinol, 1.2 g (5.0 mmol) of p-dibromobenzene, 0.05 g (0.25 mmol)copper (I) iodide, 13 mL of N,N-dimethylformamide (DMF) and 3 mL oftoluene. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 137-140° C. ° C. under argon for 8 hours. Duringthe first several hours of reflux, 8.2 g (25.0 mmol) of pulverizedcesium carbonate was added in four portions and water formed as abyproduct was removed from the reaction mixture by azeotropicdistillation. The progress of the reaction was monitored by FTIRspectroscopy. When complete conversion to the hydroxy-terminatedaromatic ether oligomer was indicated by FTIR, refluxing was stopped andtoluene was removed from the reaction mixture by distillation. When thetemperature of the reaction mixture reached 150° C., it was assumed thatall the toluene had been removed. The reaction mixture was then refluxedat 150° C. for an additional 4 hours before cooling to room temperature.After cooling, the reaction mixture was poured into 5% sodium hydroxideand the solution was filtered to remove residual copper (I) iodide. Thesolution was then made acidic with concentrated hydrochloric acid. Thesolid precipitate that formed was extracted by washing 3 times withdiethyl ether. The ether extracts were separated, dried over sodiumsulfate, filtered, and solvent was removed by vacuum under ambientconditions. The vacuum dried hydroxy-terminated aromatic ether oligomerweighed 1.1 g (73%).

EXAMPLE 6

Synthesis of hydroxy-terminated aromatic ether oligomer (n=2) fromresorcinol and m-dibromobenzene with copper (I) bromide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 1.1 g (10.0 mmol)of resorcinol, 1.2 g (5.0 mmol) of m-dibromobenzene, 0.04 g (0.25 mmol)copper (I) bromide, 20 mL of N,N-dimethylformamide (DMF) and 10 mL oftoluene. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 130-131° C. ° C. under argon for 7 hours. Duringthe first several hours of reflux, 8.2 g (25.0 mmol) of pulverizedcesium carbonate was added in four portions and water formed as abyproduct was removed from the reaction mixture by azeotropicdistillation. The progress of the reaction was monitored by FTIRspectroscopy. When complete conversion to the hydroxy-terminatedaromatic ether oligomer was indicated by FTIR, refluxing was stopped andtoluene was removed from the reaction mixture by distillation. When thetemperature of the reaction mixture reached 150° C., it was assumed thatall the toluene had been removed. The reaction mixture was then cooledto room temperature. After cooling, the reaction mixture was poured into5% sodium hydroxide and the solution was filtered to remove residualcopper (I) bromide. The solution was then made acidic with concentratedhydrochloric acid. The solid precipitate that formed was extracted bywashing 3 times with diethyl ether. The ether extracts were separated,dried over sodium sulfate, filtered, and solvent was removed by vacuumunder ambient conditions. The vacuum dried hydroxy-terminated aromaticether oligomer weighed 1.4 g (93%).

EXAMPLE 7

Synthesis of hydroxy-terminated aromatic ether oligomer (n=2) fromresorcinol and p-dibromobenzene with copper (I) bromide—To a 100 mL,3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 1.1 g (10.0 mmol)of resorcinol, 1.2 g (5.0 mmol) of m-dibromobenzene, 0.04 g (0.25 mmol)copper (I) bromide, 20 mL of N,N-dimethylformamide (DMF) and 10 mL oftoluene. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 130-131° C. ° C. under argon for 7 hours. Duringthe first several hours of reflux, 8.2 g (25.0 mmol) of pulverizedcesium carbonate was added in four portions and water formed as abyproduct was removed from the reaction mixture by azeotropicdistillation. The progress of the reaction was monitored by FTIRspectroscopy. When complete conversion to the hydroxy-terminatedaromatic ether oligomer was indicated by FTIR, refluxing was stopped andtoluene was removed from the reaction mixture by distillation. When thetemperature of the reaction mixture reached 150° C., it was assumed thatall the toluene had been removed. The reaction mixture was then cooledto room temperature. After cooling, the reaction mixture was poured into5% sodium hydroxide and the solution was filtered to remove residualcopper (I) bromide. The solution was then made acidic with concentratedhydrochloric acid. The solid precipitate that formed was extracted bywashing 3 times with diethyl ether. The ether extracts were separated,dried over sodium sulfate, filtered, and solvent was removed by vacuumunder ambient conditions. The vacuum dried hydroxy-terminated aromaticether oligomer weighed 1.3 g (87%).

EXAMPLE 8

Synthesis of m-bis[m-(m-phenoxyphenoxy)phenoxy]benzene aryl-terminatedaromatic ether oligomer from hydroxy-terminated aromatic ether oligomer(n=4)—To a 25 mL, 3-neck flask fitted with a thermometer, a Dean-Starktrap, a water-cooled condenser and an argon inlet were added 0.5 g (1.0mmol) of the 3:2 hydroxy-terminated aromatic ether oligomer prepared asin Example 2, 0.4 g (2.0 mmol) of iodobenzene, 0.3 g (1.0 mmol) ofcesium carbonate, 0.02 g (0.1 mmol) copper (I) iodide, 7 mL ofN,N-dimethylformamide (DMF), 3.5 mL of toluene, and 0.06 mL of ethylacetate. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 128° C. under argon for 129 hours. During thistime, water was removed from the reaction mixture by azeotropicdistillation. The progress of the reaction was monitored by FTIRspectroscopy. When complete conversion to the aryl-terminated aromaticether oligomer was indicated by FTIR, refluxing was stopped and thetoluene was removed by distillation. When the temperature of thereaction mixture reached 150° C., it was assumed that the toluene hadbeen removed. The reaction mixture was then cooled to room temperature.After cooling, the mixture was poured into 5% sodium hydroxide andextracted 3 times with methylene chloride. The methylene chloride layerwas separated, dried over sodium sulfate, filtered, and solvent wasremoved by vacuum under ambient conditions. The vacuum driedaryl-terminated aromatic ether oligomer weighed 0.13 g (21%).

EXAMPLE 9

Synthesis of m-bis[m-(m-phenoxyphenoxy)phenoxy]benzene aryl-terminatedaromatic ether oligomer in one step from resorcinol and m-diiodobenzenewith copper (I) iodide—To a 15 mL, 3-neck flask fitted with athermometer, a Dean-Stark trap, a water-cooled condenser and an argoninlet were added 0.6 g (5.0 mmol) resorcinol, 1.1 g (3:3 mmol) ofm-diiodobenzene, 1.6 g (5.0 mmol) of cesium carbonate, 0.03 g (0.2 mmol)copper (I) iodide, 3.5 mL of N,N-dimethylformamide (DMF), 2.0 mL oftoluene, and 0.03 mL of ethyl acetate. The Dean-Stark trap was filledwith toluene. The reaction mixture was refluxed at 125° C. under argonfor 22 hours. During this time, water was removed from the reactionmixture by azeotropic distillation. The progress of the reaction wasmonitored by FTIR spectroscopy. When complete conversion tohydroxy-terminated aromatic ether oligomer was indicated by FIR, thereaction mixture was cooled to room temperature and 0.7 g (3.3 mmol) ofiodobenzene were added to the reaction flask. After the addition, thereaction mixture was again brought to reflux and the second reaction wasallowed to proceed for 17 hours while the progress of the reaction wasmonitored by FTIR spectroscopy. When complete conversion toaryl-terminated aromatic ether oligomer was indicated by FTIR, thetoluene was removed by distillation. When the temperature of thereaction mixture reached 150° C., it was assumed that the toluene hadbeen removed. The reaction mixture was then cooled to room temperature.After cooling, the mixture was poured into 5% sodium hydroxide andextracted 3 times with methylene chloride. The methylene chloride layerwas separated, dried over sodium sulfate, filtered, and solvent wasremoved by vacuum under ambient conditions. The vacuum driedaryl-terminated aromatic ether oligomer weighed 0.4 g (44%).

B. Synthesis of Phthalonitrile Monomer

EXAMPLE 10

Synthesis phthalonitrile monomer (n=2)—To a 50 mL, 3-neck flask fittedwith a thermometer, a Dean-Stark trap, a water-cooled condenser and anargon inlet were added 3.0 g (10.4 mmol) of the 2:1 hydroxy-terminatedaromatic ether oligomer prepared as in Example 1, 15 mL dimethylsulfoxide (DMSO), and 5 mL toluene. The Dean-Stark trap was filled withtoluene. The reaction mixture was refluxed at 140° C. under argon for 4hours. Anhydrous, pulverized potassium carbonate 5.8 g (41.7 mmol) wasthen added to the reaction mixture in 4 equal portions over 4 hourswhile continuing the reflux. During this time, water formed as abyproduct was removed azeotropically. After the carbonate additions, thesolution was refluxed an additional 2.5 hours until no more waterappeared in the Dean-Stark trap. Toluene was then removed from thereaction mixture by distillation. When the temperature of the reactionmixture reached 180° C., it was assumed that the toluene had beenremoved. After removal of the toluene, the reaction mixture was cooledto room temperature and 3.6 g (20.8 mmol) of 4-nitrophthalonitrile wasadded in one portion. The resulting reaction mixture was heated to65-75° C. and stirred at this temperature for 15 hours. The progress ofthe reaction was monitored by FTIR spectroscopy. After 15 hours, theFTIR spectrum showed the complete disappearance of absorptionsattributed to the nitro and hydroxyl groups. The reaction mixture wascooled to room temperature and poured slowly into 400 mL of dilutehydrochloric acid with rapid stirring to break the precipitate intosmall particles. The solid product was collected by suction filtration,washed exhaustively with water, and dried to give 4.2 g (77%) of thephthalonitrile monomer. A DSC thermogram showed an endothermictransition at 155° C. attributed to the melting of the phthalonitrilemonomer.

EXAMPLE 11

Synthesis phthalonitrile monomer (n=4)—To a 50 mL, 3-neck flask fittedwith a thermometer, a Dean-Stark trap, a water-cooled condenser and anargon inlet were added 3.3 g (6.9 mmol) of the 3:2 hydroxy-terminatedaromatic ether oligomer prepared as in Example 2, 15 mL dimethylsulfoxide (DMSO), and 5 mL toluene. The Dean-Stark trap was filled withtoluene. The reaction mixture was refluxed at 140° C. under argon for3.5 hours. Anhydrous, pulverized potassium carbonate 2.0 g (14.8 mmol)was then added to the reaction mixture in 4 equal portions over 3 hourswhile continuing the reflux. During this time, water formed as abyproduct was removed azeotropically. After the carbonate additions, thesolution was refluxed an additional 4 hours until no more water appearedin the Dean-Stark trap. Toluene was then removed from the reactionmixture by distillation. When the temperature of the reaction mixturereached 180° C., it was assumed that the toluene had been removed. Afterremoval of the toluene, the reaction mixture was cooled to roomtemperature and 2.4 g (13.8 mmol) of 4-nitrophthalonitrile was added inone portion. The resulting reaction mixture was heated to 70-75° C. andstirred at this temperature for approximately 24 hours. The progress ofthe reaction was monitored by FTIR spectroscopy. After 24 hours, theFTIR spectrum showed the complete disappearance of absorptionsattributed to the nitro and hydroxyl groups. The reaction mixture wascooled to room temperature and poured slowly into 400 mL of dilutehydrochloric acid with rapid stirring to break the precipitate intosmall particles. The solid product was collected by suction filtration,washed exhaustively with water, and dried to give 4.4 g (88%) of thephthalonitrile monomer. A DSC thermogram showed an endothermictransition at 147° C. attributed to the melting of the phthalonitrilemonomer.

EXAMPLE 12

Synthesis phthalonitrile monomer (n=8)—To a 50 mL, 3-neck flask fittedwith a thermometer, a Dean-Stark trap, a water-cooled condenser and anargon inlet were added 1.0 g (1.2 mmol) of the 5:4 hydroxy-terminatedaromatic ether oligomer prepared as in Example 3, 7 mL dimethylsulfoxide (DMSO), and 4 mL toluene. The Dean-Stark trap was filled withtoluene. The reaction mixture was refluxed at 130° C. under argon for 3hours. Anhydrous, pulverized potassium carbonate 0.7 g (5.0 mmol) wasthen added to the reaction mixture in 4 equal portions over 3 hourswhile continuing the reflux. During this time, water formed as abyproduct was removed azeotropically. After the carbonate additions, thesolution was refluxed an additional 2 hours until no more water appearedin the Dean-Stark trap. Toluene was then removed from the reactionmixture by distillation. When the temperature of the reaction mixturereached 150° C., it was assumed that the toluene had been removed. Thereaction mixture was cooled to room temperature and 0.4 g (2.4 mmol) of4-nitrophthalonitrile was added in one portion. The resulting reactionmixture was heated to 65-70° C. and stirred at this temperature for 4hours. The temperature of the reaction mixture was then lowered to 40°C. and the reaction was allowed to continue for another 44 h. Theprogress of the reaction was monitored by FTIR spectroscopy. After 48hours, the FTIR spectrum showed the complete disappearance ofabsorptions attributed to the nitro and hydroxyl groups. The reactionmixture was cooled to room temperature and poured slowly into 400 mL ofdilute hydrochloric acid with rapid stirring to break the precipitateinto small particles. The solid product was collected by suctionfiltration, washed exhaustively with water, and dried to give 1.0 g(77%) of the phthalonitrile monomer.

EXAMPLE 13

Synthesis of phthalonitrile monomer (n=6) in a one pot, two stepreaction from resorcinol and m-diiodobenzene with copper (I) iodide—To a25 mL, 3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 0.9 g (8.0 mmol) ofresorcinol, 2.0 g (6.0 mmol) of m-diiodobenzene, 2.6 g (8.0 mmol) ofcesium carbonate, 0.06 g (0.3 mmol) copper (I) iodide, 10 mL ofN,N-dimethylformamide (DMF), and 4 mL of toluene. The Dean-Stark trapwas filled with toluene. The reaction mixture was refluxed at 120° C.under argon for 12 hours. During this time, water was removed from thereaction mixture by azeotropic distillation. The progress of thereaction was monitored by FTIR spectroscopy. When complete conversion tothe hydroxy-terminated aromatic ether oligomer was indicated by FTIR,the toluene was removed from the reaction mixture by distillation. Whenthe temperature of the reaction mixture reached 150° C., it was assumedthat the toluene had been removed. The reaction mixture was then cooledto room temperature and 0.7 g (4.0 mmol) of 4-nitrophthalonitrile wasadded in one portion. The resulting reaction mixture was heated to40-60° C. and stirred at this temperature overnight. After 16 hours, theFTIR spectrum showed the complete disappearance of absorptionsattributed to the nitro and hydroxyl groups. The reaction mixture wascooled to room temperature and poured slowly into 400 mL of dilutehydrochloric acid with rapid stirring to break the precipitate intosmall particles. The solid product was collected by suction filtration,washed exhaustively with water, and dried to give 1.8 g (98%) of thephthalonitrile monomer.

EXAMPLE 14

Synthesis of phthalonitrile monomer (n=2) in a one pot, two stepreaction from resorcinol and m-dibromobenzene with copper (I) iodide—Toa 100 mL, 3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 4.4 g (40.0 mmol)of resorcinol, 4.7 g (20.0 mmol) of m-dibromobenzene, 13.0 g (40.0 mmol)of cesium carbonate, 0.2 g (1.0 mmol) copper (I) iodide, 25 mL ofN,N-dimethylformamide (DMF), and 8 mL of toluene. The Dean-Stark trapwas filled with toluene. The reaction mixture was refluxed at 130° C.under argon for 18 hours. During this time, water was removed from thereaction mixture by azeotropic distillation. The progress of thereaction was monitored by FTIR spectroscopy. When complete conversion tothe hydroxy-terminated aromatic ether oligomer was indicated by FTIR,the toluene was removed from the reaction mixture by distillation. Whenthe temperature of the reaction mixture reached 150° C., it was assumedthat the toluene had been removed. The reaction mixture was then cooledto room temperature and 1.7 g (10.0 mmol) of 4-nitrophthalonitrile wasadded in one portion. The resulting reaction mixture was heated to60-80° C. and stirred at this temperature for 8 hours. After 8 hours,the FTIR spectrum showed the complete disappearance of absorptionsattributed to the nitro and hydroxyl groups. The reaction mixture wascooled to room temperature and poured slowly into a 2 liter beakercontaining dilute hydrochloric acid with rapid stirring to break theprecipitate into small particles. The solid product was collected bysuction filtration, washed exhaustively with water, and dried to give9.0 g (82%) of the phthalonitrile monomer.

EXAMPLE 15

Synthesis of phthalonitrile monomer (n=4) in a one pot, two stepreaction from resorcinol and m-dibromobenzene with copper (I) iodide—Toa 100 mL, 3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 6.6 g (60.0 mmol)of resorcinol, 9.5 g (40.0 mmol) of m-dibromobenzene, 23.2 g (71.2 mmol)of cesium carbonate, 0.4 g (2.0 mmol) copper (I) iodide, 25 mL ofN,N-dimethylformamide (DMF), and 10 mL of toluene. The Dean-Stark trapwas filled with toluene. The reaction mixture was refluxed at 136° C.under argon for 18 hours. During this time, water was removed from thereaction mixture by azeotropic distillation. The progress of thereaction was monitored by FTIR spectroscopy. When complete conversion tothe hydroxy-terminated aromatic ether oligomer was indicated by FTIR,the toluene was removed from the reaction mixture by distillation. Whenthe temperature of the reaction mixture reached 150° C., it was assumedthat the toluene had been removed. The reaction mixture was then cooledto room temperature and 7.0 g (40.0 mmol) of 4-nitrophthalonitrile wasadded in one portion. The resulting reaction mixture was heated to65-80° C. and stirred at this temperature for 26 hours. After 26 hours,the FTIR spectrum showed the complete disappearance of absorptionsattributed to the nitro and hydroxyl groups. The reaction mixture wascooled to room temperature and poured slowly into a 2 liter beakercontaining dilute hydrochloric acid with rapid stirring to break theprecipitate into small particles. The solid product was collected bysuction filtration, washed exhaustively with water, and dried to give11.1 g (76%) of the phthalonitrile monomer.

EXAMPLE 16

Synthesis of phthalonitrile monomer (n=2) in a one pot, two stepreaction from resorcinol and m-dibromobenzene with copper (I) bromide—Toa 25 mL, 3-neck flask fitted with a thermometer, a Dean-Stark trap, awater-cooled condenser and an argon inlet were added 1.1 g (10.0 mmol)of resorcinol, 1.2 g (5.0 mmol) of m-dibromobenzene, 0.04 g (0.25 mmol)copper (I) bromide, 10 mL of N,N-dimethylformamide (DMF) and 3 mL oftoluene. The Dean-Stark trap was filled with toluene. The reactionmixture was refluxed at 135-140° C. under argon for 6 hours. During thistime, anhydrous, pulverized potassium carbonate 3.4 g (10.5 mmol) wasadded to the reaction mixture in 3 portions and water formed as areaction byproduct was removed azeotropically. The progress of thereaction was monitored by FTIR spectroscopy. When no more water appearedin the Dean-Stark trap, the toluene was removed from the reactionmixture by distillation. It was assumed that all the toluene had beenremoved when the temperature of the reaction mixture reached 150° C. Thereaction mixture was then refluxed an additional 6 hours at 150° C. Whencomplete conversion to the hydroxy-terminated aromatic ether oligomerwas indicated by FTIR, the reaction mixture was cooled to roomtemperature and 1.7 g (10.0 mmol) of 4-nitrophthalonitrile was added inone portion. The resulting mixture was heated to 70-80° C. and stirredat this temperature for 15 hours. After 15 hours, the FTIR spectrumstill showed small peaks attributed to the nitro and hydroxyl groups.The reaction mixture was cooled to room temperature and 0.5 g (3.6 mmol)of potassium carbonate was added in one portion. After the addition, thereaction mixture was reheated to 75° C. for 4 hours. Since FTIRspectroscopy showed the complete disappearance of absorptions attributedto the nitro and hydroxyl groups after the 4 hours, the reaction mixturewas cooled to room temperature and poured slowly into a 2 liter beakercontaining dilute hydrochloric acid with rapid stirring to break theprecipitate into small particles. The solid product was collected bysuction filtration, washed exhaustively with water, and dried to give1.3 g (48%) of the phthalonitrile monomer.

C. Curing of Phthalonitrile Monomer

EXAMPLE 17

Curing of phthalonitrile monomer (n=4) at 200° C. in the presence of 7.9wt % of p-BAPS followed by post-cure at 375° C. for 2 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 11 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 7.9 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 4.5 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 2 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 18

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 2.0wt % of p-APB followed by post-cure at 375° C. for 2 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 2.0 wt %) with stirring. The darkcuring mixture was cured by heating at 200° C. for 4.5 hours. Gelationoccurred during the heat treatment. The thermoset was post-cured at 300°C. for 1 hour and at 375° C. for 2 hours under nitrogen. The thermal andoxidative stability of the thermoset as determined by TGA was found tobe a function of curing additive and curing temperature. The thermosetshowed superb thermal stability when cured at 200° C. Further heating to375° C. under inert conditions resulted in an improvement in the thermalstability. The thermo-oxidative properties were investigated between 25°C. and 1000° C. Samples of the thermoset were compared in relation tothe temperature that the materials commenced to lose weight andcatastrophic decomposition occurred. The thermoset showed excellentoxidative stability when cured at 200° C. The thermoset commenced tolose weight at a higher temperature upon postcuring at 375° C.indicating an improvement in the oxidative stability.

EXAMPLE 19

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 2.0wt % of p-APB followed by post-cure at 375° C. for 5 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 2.0 wt %) with stirring. The darkcuring mixture was cured by heating at 200° C. for 4.5 hours. Gelationoccurred during the heat treatment. The thermoset was post-cured at 300°C. for 1 hour and at 375° C. for 5 hours under nitrogen. The thermal andoxidative stability of the thermoset as determined by TGA was found tobe a function of curing additive and curing temperature. The thermosetshowed superb thermal stability when cured at 200° C. Further heating to375° C. under inert conditions resulted in an improvement in the thermalstability. The thermo-oxidative properties were investigated between 25°C and 1000° C. Samples of the thermoset were compared in relation to thetemperature that the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 20

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 2.9wt % of p-BAPS followed by post-cure at 375° C. for 2 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 2.9 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 4.5 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 2 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 21

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 2.9wt % of p-BAPS followed by post-cure at 375° C. for 5 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 2.9 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 4.5 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 5 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 22

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 1.7wt % of p-APB followed by post-cure at 375° C. for 8 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 1.7 wt %) with stirring. The darkcuring mixture was cured by heating at 200° C. for 4.5 hours. Gelationoccurred during the heat treatment. The thermoset was post-cured at 300°C. for 1 hour and at 375° C. for 8 hours under nitrogen. The thermal andoxidative stability of the thermoset as determined by TGA was found tobe a function of curing additive and curing temperature. The thermosetshowed superb thermal stability when cured at 200° C. Further heating to375° C. under inert conditions resulted in an improvement in the thermalstability. The thermo-oxidative properties were investigated between 25°C. and 1000° C. Samples of the thermoset were compared in relation tothe temperature that the materials commenced to lose weight andcatastrophic decomposition occurred. The thermoset showed excellentoxidative stability when cured at 200° C. The thermoset commenced tolose weight at a higher temperature upon postcuring at 375° C.indicating an improvement in the oxidative stability.

EXAMPLE 23

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 2.5wt % of p-BAPS followed by post-cure at 375° C. for 8 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 2.5 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 4.5 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 8 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 24

Curing of phthalonitrile monomer (n=2) at 160° C. in the presence of 4.8wt % of p-APB followed by post-cure at 375° C. for 16 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 4.8 wt %) with stirring. The darkcuring mixture was cured by heating at 160° C. for 2 hours. Gelationoccurred during the heat treatment. The thermoset was post-cured at 300°C. for 1 hour and at 375° C. for 16 hours under nitrogen. The thermaland oxidative stability of the thermoset as determined by TGA was foundto be a function of curing additive and curing temperature. Thethermoset showed superb thermal stability when cured at 200° C. Furtherheating to 375° C. under inert conditions resulted in an improvement inthe thermal stability. The thermo-oxidative properties were investigatedbetween 25° C. and 1000° C. Samples of the thermoset were compared inrelation to the temperature that the materials commenced to lose weightand catastrophic decomposition occurred. The thermoset showed excellentoxidative stability when cured at 200° C. The thermoset commenced tolose weight at a higher temperature upon postcuring at 375° C.indicating an improvement in the oxidative stability.

EXAMPLE 25

Curing of phthalonitrile monomer (n=2) at 160° C. in the presence of 7.0wt % of p-BAPS followed by post-cure at 375° C. for 16 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 7.0 wt %) with stirring.The dark curing mixture was cured by heating at 160° C. for 2 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 16 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 26

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 4.7wt % of p-APB followed by post-cure at 375° C. for 8 hours and thermaland oxidative stability measurement—To the melt of phthalonitrilemonomer at 200° C. prepared as in Example 10 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 4.7 wt %) with stirring. The darkcuring mixture was cured by heating at 200° C. for 3 hours. Gelationoccurred during the heat treatment. The thermoset was post-cured at 300°C. for 1 hour and at 375° C. for 8 hours under nitrogen. The thermal andoxidative stability of the thermoset as determined by TGA was found tobe a function of curing additive and curing temperature. The thermosetshowed superb thermal stability when cured at 200° C. Further heating to375° C. under inert conditions resulted in an improvement in the thermalstability. The thermo-oxidative properties were investigated between 25°C. and 1000° C. Samples of the thermoset were compared in relation tothe temperature that the materials commenced to lose weight andcatastrophic decomposition occurred. The thermoset showed excellentoxidative stability when cured at 200° C. The thermoset commenced tolose weight at a higher temperature upon postcuring at 375° C.indicating an improvement in the oxidative stability.

EXAMPLE 27

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 7.0wt % of p-BAPS post-cure at 375° C. for 8 hours and thermal andoxidative stability measurement—To the melt of phthalonitrile monomer at200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 7.0 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 3 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 8 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The-thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 28

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of23.3 wt % of p-BAPS followed by post-cure at 375° C. for 8 hours andthermal and oxidative stability measurement—To the melt ofphthalonitrile monomer at 200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 23.3 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 2 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 8 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 29

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of15.7 wt % of p-BAPS followed by post-cure at 375° C. for 8 hours andthermal and oxidative stability measurement—To the melt ofphthalonitrile monomer at 200° C. prepared as in Example 10 was addedbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS, 15.7 wt %) with stirring.The dark curing mixture was cured by heating at 200° C. for 2 hours.Gelation occurred during the heat treatment. The thermoset waspost-cured at 300° C. for 1 hour and at 375° C. for 8 hours undernitrogen. The thermal and oxidative stability of the thermoset asdetermined by TGA was found to be a function of curing additive andcuring temperature. The thermoset showed superb thermal stability whencured at 200° C. Further heating to 375° C. under inert conditionsresulted in an improvement in the thermal stability. Thethermo-oxidative properties were investigated between 25° C. and 1000°C. Samples of the thermoset were compared in relation to the temperaturethat the materials commenced to lose weight and catastrophicdecomposition occurred. The thermoset showed excellent oxidativestability when cured at 200° C. The thermoset commenced to lose weightat a higher temperature upon postcuring at 375° C. indicating animprovement in the oxidative stability.

EXAMPLE 30

Curing of phthalonitrile monomer (n=2) at 150° C. in the presence of 4.8wt % of p-APB followed by post-cure at 200° C. for 5 hours and DSCthermogram to 450° C.—To the melt of phthalonitrile monomer at 150° C.prepared as in Example 10 was added 1,4-bis(3-aminophenoxy)benzene(p-APB, 4.8 wt %) with stirring. The dark curing mixture was cured byheating at 150° C. for 2 hours. Gelation occurred during the heattreatment. A small sample (˜2 mg) of this material was placed in a DSCpan. A sample of the cured thermoset was post-cured at 200° C. for 5hours under nitrogen in a DSC pan. A DSC thermogram from 25° to 450° C.of the post-cured sample showed only one small exothermic transition at300° C. attributed to the reaction of APB with the phthalonitrilemonomer. Upon cooling and rerunning the same post-cured sample, notransitions were seen in the DSC thermogram and therefore the sample wasassumed to be fully cured.

EXAMPLE 31

Curing of phthalonitrile monomer (n=2) at 150° C. in the presence of 4.8wt % of p-APB followed by post-cure at 200° C. for 8 hours and DSCthermogram to 450° C.—To the melt of phthalonitrile monomer at 150° C.prepared as in Example 10 was added 1,4-bis(3-aminophenoxy)benzene(p-APB, 4.8 wt %) with stirring. The dark curing mixture was cured byheating at 150° C. for 2 hours. Gelation occurred during the heattreatment. A sample of the cured thermoset was post-cured at 200° C. for8 hours under nitrogen in a DSC pan. A DSC thermogram from 25° to 450°C. of the post-cured sample showed a small exothermic transition at 300°C. attributed to the reaction of APB with the phthalonitrile monomer.Upon cooling and rerunning the same post-cured sample, no transitionswere seen in the DSC thermogram. The lack of transitions indicated thatno further reaction of APB with the phthalonitrile monomer had occurred.

EXAMPLE 32

Curing of phthalonitrile monomer (n=2) at 150° C. in the presence of 7.0wt % of p-BAPS followed by post-cure at 200° C. for 5 hours and DSCthermogram to 450° C.—To the melt of phthalonitrile monomer at 150° C.prepared as in Example 10 was added bis[4-(4-aminophenoxy)phenyl]sulfone(p-BAPS, 7.0 wt %) with stirring. The dark curing mixture was cured byheating at 150° C. for 2 hours. Gelation occurred during the heattreatment. A sample of the cured thermoset was post-cured at 200° C. for5 hours under nitrogen in a DSC pan. A DSC thermogram from 25° to 450°C. of the post-cured sample showed no transitions. The lack oftransitions indicated that no further reaction of APB with thephthalonitrile monomer had occurred.

EXAMPLE 33

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 4.7wt % of p-APB and DSC thermogram to 450° C.—To the melt ofphthalonitrile monomer at 200° C. prepared as in Example 10 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 4.7 wt %) with stirring. The darkcuring mixture was cured by heating at 200° C. for 3 hours. Gelationoccurred during the heat treatment. A small sample (˜2 mg) of thismaterial was placed in a DSC pan. The DSC thermogram from 25° to 450° C.showed two small exothermic transitions at 246° C. and at ˜385° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 34

Curing of phthalonitrile monomer (n=2) at 200° C. in the presence of 7.0wt % of p-BAPS followed by post-cure at 200° C. for 5 hours and DSCthermogram to 450° C.—To the melt of phthalonitrile monomer at 200° C.prepared as in Example 10 was added bis[4-(4-aminophenoxy)phenyl]sulfone(p-BAPS, 7.0 wt %) with stirring. The dark curing mixture was cured byheating at 200° C. for 3 hours. Gelation occurred during the heattreatment. A small sample (˜2 mg) of the cured material was placed in aDSC pan. The DSC thermogram from 25° C. to 450° C. showed two exothermictransitions at 234° C. and at ˜375° C. attributed to reaction of APBwith the phthalonitrile monomer. A second sample of the same thermosetwas post-cured at 200° C. for 5 hours under nitrogen in a DSC pan. A DSCthermogram from 25° to 450° C. of the post-cured sample showed twoexothermic transitions at 300° C. and at 365° C. attributed to thereaction of BAPS with the phthalonitrile monomer. The results indicatethat the phthalonitrile monomer had not fully reacted under theconditions at 200° C.

EXAMPLE 35

DSC thermogram of phthalonitrile monomer (n=2) in the presence of 12.5wt % diphenylamine and DSC thermogram to 450° C.—To the phthalonitrilemonomer prepared as in Example 10 was added 12.5 wt % diphenylamine in aDSC pan. The DSC thermogram from 25° C. to 450° C. showed twoendothermic transitions at 52° C. and at 61° C. attributed to melting ofthe additive and the phthalonitrile monomer, respectively, and an twoexothermic transitions at 183° C. and ˜270° C. attributed to reaction ofthe amine with the phthalonitrile monomer.

EXAMPLE 36

DSC thermogram of phthalonitrile monomer (n=2) in the presence of 3.6 wt% diphenylamine and DSC thermogram to 450° C.—To the phthalonitrilemonomer prepared as in Example 10 was added 3.6 wt % diphenylamine in aDSC pan. The DSC thermogram from 25° C. to 450° C. showed twoendothermic transitions at 50° C. and at 62° C. attributed to melting ofthe additive and the phthalonitrile monomer. respectively, and an twoexothermic transitions at 185° C. and ˜270° C. attributed to reaction ofthe amine with the phthalonitrile monomer.

EXAMPLE 37

DSC thermogram of phthalonitrile monomer (n=2) in the presence of 13.9wt % 1,3-phenylenediamine and DSC thermogram to 450° C.—To thephthalonitrile monomer prepared as in Example 10 was added 13.9 wt %1,3-phenylenediamine in a DSC pan. The DSC thermogram from 25° C. to450° C. showed an endothermic transition at 61° C. attributed to themelting of both the additive and the phthalonitrile monomer, and anexothermic transition at 242° C. attributed to reaction of the aminewith the phthalonitrile monomer.

EXAMPLE 38

DSC thermogram of phthalonitrile monomer (n=2) in the presence of 3.5 wt% 1,3-phenylenediamine and DSC thermogram to 450° C.—To thephthalonitrile monomer prepared as in Example 10 was added 3.5 wt %1,3-phenylenediamine in a DSC pan. The DSC thermogram from 25° C. to450° C. showed an endothermic transition at 61° C. attributed to themelting of both the additive and the phthalonitrile monomer, and anexothermic transition at 255° C. attributed to reaction of the aminewith the phthalonitrile monomer.

EXAMPLE 39

DSC thermogram of phthalonitrile monomer (n=2) in the presence of 6.3 wt% of p-toluenesulfonic acid and DSC thermogram to 450° C.—To thephthalonitrile monomer prepared as in Example 10 was added 6.3 wt %p-toluenesulfonic acid in a DSC pan. The DSC thermogram from 25° C. to450° C. showed two endothermic transitions at 62° C. and at 103° C.attributed to melting of the phthalonitrile monomer and the additive,respectively, and an exothermic transition at 299° C. attributed toreaction of the acid with the phthalonitrile monomer.

EXAMPLE 40

Curing of 50:50 blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl at 250° C. in the presence of 2.8wt % of p-BAPS and DSC thermogram to 450° C.—A sample containing 25 mgof the phthalonitrile monomer prepared as in Example 10, 25 mg of4.4′-bis(3,4-dicyanophenoxy)biphenyl and 1.5 mg (2.8 wt %) ofbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS) in an aluminum planchetwas at 250° C. with stirring. The blend was cured by heating in air at250° C. for 4 hours. Gelation occurred during the heat treatment. A DSCthermogram of the cured material from 25° C. to 450° C. showed notransitions. The lack of transitions indicated that no further reactionof BAPS with the phthalonitrile monomer had occurred.

EXAMPLE 41

Curing of 25:75 blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl at 250° C. in the presence of 2.8wt % of p-BAPS and DSC thermogram to 450° C.—A sample containing 12 mgof the phthalonitrile monomer prepared as in Example 10, 38 mg of4,4′-bis(3,4-dicyanophenoxy)biphenyl and 1.5 mg (2.8 wt %) ofbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS) in an aluminum planchetwas melted at 250° C. with stirring. The blend was cured by heating inair at 250° C. for 4 hours. Gelation occurred during the heat treatment.A DSC thermogram of the cured material from 25° C. to 450° C. showed notransitions. The lack of transitions indicated that no further reactionof BAPS with the phthalonitrile monomer had occurred.

EXAMPLE 42

Curing of 75:25 blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl at 250° C. in the presence of 2.8wt % of p-BAPS and DSC thermogram to 450° C.—A sample containing 38 mgof the phthalonitrile monomer prepared as in Example 10, 13 mg of4,4′-bis(3,4-dicyanophenoxy)biphenyl and 1.5 mg (2.8 wt %) ofbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS) in an aluminum planchetwas melted at 250° C. with stirring. The blend was cured by heating inair at 250° C. for 4 hours. Gelation occurred during the heat treatment.A DSC thermogram of the cured material from 25° C. to 450° C. showed notransitions. The lack of transitions indicated that no further reactionof BAPS with the phthalonitrile monomer had occurred.

EXAMPLE 43

Curing of 50:50 blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl at 250° C. in the presence of 2.0wt % of p-BAPS—A sample containing 1.58 mg of the phthalonitrile monomerprepared as in Example 10, 1.45 mg 4,4′-bis(3,4-dicyanophenoxy)biphenyland 0.06 mg (2.0 wt %) of bis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS)was weighed into a DSC pan. The DSC thermogram from 25° C. to 450° C.showed two endothermic transitions at 61° C. and at 213° C. attributedto melting of the phthalonitrile monomers and an exothermic transitionat 262° C. attributed to reaction of the amine with the phthalonitrilemonomers.

EXAMPLE 44

Curing of 75:25 blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl at 250° C. in the presence of 2.3wt % of p-BAPS—A sample containing 2.75 mg of the phthalonitrile monomerprepared as in Example 10, 1.09 mg of4,4′-bis(3,4-dicyanophenoxy)biphenyl and 0.09 mg (2.3 wt %) ofbis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS) was weighed into a DSCpan. The DSC thermogram from 25° C. to 450° C. showed two endothermictransitions at 63° C. and at 212° C. attributed to melting of thephthalonitrile monomers and an exothermic transition at 259° C.attributed to reaction of the amine with the phthalonitrile monomers.

EXAMPLE 45

Curing of 25:75 blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl at 250° C. in the presence of 3.0wt % of p-BAPS—A sample containing 0.93 mg of the phthalonitrile monomerprepared as in Example 10, 2.95 mg 4,4′-bis(3,4-dicyanophenoxy)biphenyland 0.12 mg (3.0 wt %) of bis[4-(4-aminophenoxy)phenyl]sulfone (p-BAPS)was weighed into a DSC pan. The DSC thermogram from 25° C. to 450° C.showed two endothermic transitions at 63° C. and at 226° C. attributedto melting of the phthalonitrile monomers and an exothermic transitionat 264° C. attributed to reaction of the amine with the phthalonitrilemonomers.

EXAMPLE 46

DSC thermogram of blend of phthalonitrile monomer (n=2) and4,4′-bis(3,4-dicyanophenoxy)biphenyl—A sample containing 1.30 mg of thephthalonitrile monomer prepared as in Example 10 and 1.40 mg of4,4′-bis(3,4-dicyanophenoxy)biphenyl was weighed into a DSC pan. Aninitial DSC thermogram from 25° C. to 270° C. showed two endothermictransitions at 63° C. and at 220° C. attributed to melting of thephthalonitrile monomers. After the sample was cooled, a second DSCthermogram was obtained from 25° C. to 270° C. The second thermogramshowed an endothermic transition at 63° C. attributed to the oligomericphthalonitrile monomer, an endothermic transition between 185-195° C.attributed to the biphenyl phthalonitrile monomer melting at a lowertemperature and an exothermic transition at 120° C. attributed to anamorphous to crystalline phase change.

EXAMPLE 47

Curing of phthalonitrile monomer (n=2) at 120° C. in the presence of12-16 wt % of epoxy amine hardener and DSC thermogram to 400° C.—To themelt of phthalonitrile monomer at 120° C. prepared as in Example 10 wasadded epoxy amine hardener (12-16 wt %) with stirring. The dark curingmixture was cured by heating at 120° C. for 2 hours. Gelation occurredduring the heat treatment. A small sample (˜2 mg) of this material wasplaced in a DSC pan. The DSC thermogram from 25° to 400° C. showed twoexothermic transitions at ˜175° C. and at 233° C. attributed to thereaction of the amine with the phthalonitrile monomer. The thermogramalso showed an endothermic transition at 57° C. attributed to thephthalonitrile monomer.

EXAMPLE 48

Curing of phthalonitrile monomer (n=4) at 100° C. in the presence of5-10 wt % of epoxy amine hardener and DSC thermogram to 400° C.—To themelt of phthalonitrile monomer at 150° C. prepared as in Example 11 wasadded epoxy amine hardener (5-10 wt %) with stirring. After mixing, thedark curing mixture was cured by heating at 100° C. for 6.5 hours.Gelation occurred during the heat treatment. A small sample (˜2 mg) ofthis material was placed in a DSC pan. The DSC thermogram from 25° to400° C. showed an endothermic transition at 46° C. attributed to thephthalonitrile monomer and an exothermic transition at 246° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 49

Curing of phthalonitrile monomer (n=4) at 100° C. in the presence of5-10 wt % of 1,12-diaminododecane and DSC thermogram to 400° C.—To themelt of phthalonitrile monomer at 150° C. prepared as in Example 11 wasadded 1,12-diaminododecane (5-10 wt %) with stirring. After mixing, thedark curing mixture was cured by heating at 100° C. for 6.5 hours.Gelation occurred during the heat treatment. A small sample (˜2 mg) ofthis material was placed in a DSC pan. The DSC thermogram from 25° to400° C. showed an endothermic transition at 45° C. attributed to thephthalonitrile monomer and an exothermic transition at 263° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 50

Curing of phthalonitrile monomer (n=4) at 80° C. in the presence of 5-10wt % of epoxy amine hardener and DSC thermogram to 400° C.—To the meltof phthalonitrile monomer at 200° C. prepared as in Example 11 was addedepoxy amine hardener (5-10 wt %) with stirring. After mixing, the darkcuring mixture was cured by heating at 80° C. for 4 hours. Gelationoccurred during the heat treatment. A small sample (˜2 mg) of thismaterial was placed in a DSC pan. The DSC thermogram from 25° to 400° C.showed an endothermic transition at 44° C. attributed to thephthalonitrile monomer and an exothermic transition at 246° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 51

Curing of phthalonitrile monomer (n=4) at 80° C. in the presence of 5-10wt % of 1,12-diaminododecane and DSC thermogram to 400° C.—To the meltof phthalonitrile monomer at 200° C. prepared as in Example 11 was added1,12-diaminododecane (5-10 wt %) with stirring. After mixing, the darkcuring mixture was cured by heating at 80° C. for 4 hours. Gelationoccurred during the heat treatment. A small sample (˜2 mg) of thismaterial was placed in a DSC pan. The DSC thermogram from 25° to 400° C.showed an endothermic transition at 41° C. attributed to thephthalonitrile monomer and an exothermic transition at 248° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 52

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of5-10 wt % of epoxy amine hardener and DSC thermogram to 400° C.—To themelt of phthalonitrile monomer at 150° C. prepared as in Example 11 wasadded epoxy amine hardener (5-10 wt %) with stirring. After mixing, thedark curing mixture was cured by heating at 150° C. for 4 hours.Gelation occurred during the heat treatment. A small sample (˜2 mg) ofthis material was placed in a DSC pan. The DSC thermogram from 25° to400° C. showed an endothermic transition at 49° C. attributed to thephthalonitrile monomer and an exothermic transition at 270° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 53

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of5-10 wt % of 1,6-hexanediamine and DSC thermogram to 400° C.—To the meltof phthalonitrile monomer at 150° C. prepared as in Example 11 was added1,6-hexanediamine (5-10 wt %) with stirring. After mixing, the darkcuring mixture was cured by heating at 150° C. for 13 hours. Gelationoccurred during the heat treatment. A small sample (˜2 mg) of thismaterial was placed in a DSC pan. The DSC thermogram from 25° to 400° C.showed an endothermic transition at 52° C. attributed to thephthalonitrile monomer and an exothermic transition at 273° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 54

Curing of phthalonitrile monomer (n=4) at 100° C. in the presence of5-10 wt % of 1,6-hexanediamine and DSC thermogram to 400° C.—To the meltof phthalonitrile monomer at 150° C. prepared as in Example 11 was added1,6-hexanediamine (5-10 wt %) with stirring. After mixing, the darkcuring mixture was cured by heating at 100° C. for 13 hours. Gelationoccurred during the heat treatment. A small sample (˜2 mg) of thismaterial was placed in a DSC pan. The DSC thermogram from 25° to 400° C.showed an endothermic transition at 47° C. attributed to thephthalonitrile monomer and an exothermic transition at 258° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 55

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 40wt % of epoxy amine hardener and DSC thermogram to 400° C.—To the meltof phthalonitrile monomer at 150° C. prepared as in Example 11 was addedepoxy amine hardener (40 wt %) with stirring. After mixing, the darkcuring mixture was cured by heating at 150° C. for 8 hours. Gelationoccurred during the heat treatment. A small sample (˜2 mg) of thismaterial was placed in a DSC pan. The DSC thermogram from 25° to 400° C.showed an endothermic transition at 52° C. attributed to thephthalonitrile monomer and an exothermic transition at 255° C.attributed to the reaction of the amine with the phthalonitrile monomer.

EXAMPLE 56

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 40wt % 1,6-hexanediamine and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 150° C. prepared as in Example 11 was added1,6-hexanediamine (40 wt %) with stirring. After mixing, the dark curingmixture was cured by heating at 150° C. for 16 hours. Gelation occurredduring the heat treatment. A small sample (˜2 mg) of this material wasplaced in a DSC pan. The DSC thermogram from 25° to 400° C. showed notransitions. The lack of transitions indicated that no further reactionbetween the amine and the phthalonitrile monomer had occurred.

EXAMPLE 57

Curing of phthalonitrile monomer (n=2) at 150° C. in the presence of 40wt % 1,6-hexanediamine and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 150° C. prepared as in Example 10 was added1,6-hexanediamine (40 wt %) with stirring. After mixing, the dark curingmixture was cured by heating at 150° C. for 16 hours. Gelation occurredduring the heat treatment. A small sample (˜2 mg) of this material wasplaced in a DSC pan. The DSC thermogram from 25° to 400° C. showed asmall exothermic transition at 246° C. attributed to the reaction of theamine with the phthalonitrile monomer.

EXAMPLE 58

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 29wt % of 1,6-hexanediamine and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 150° C. prepared as in Example 11 was added1,6-hexanediamine (29 wt %) with stirring. After mixing, the dark curingmixture was cured by heating at 150° C. for 12 hours. Gelation occurredduring the heat treatment. A small sample (˜2 mg) of this material wasplaced in a DSC pan. The DSC thermogram from 25° to 400° C. showed anexothermic transition at 259° C. attributed to the reaction of the aminewith the phthalonitrile monomer.

EXAMPLE 59

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 17wt % of 1,6-hexanediamine and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 150° C. prepared as in Example 11 was added1,6-hexanediamine (17 wt %) with stirring. After mixing, the dark curingmixture was cured by heating at 150° C. for 12 hours. Gelation occurredduring the heat treatment. A small sample (˜2 mg) of this material wasplaced in a DSC pan. The DSC thermogram from 25° to 400° C. showed anexothermic transition at 273° C. attributed to the reaction of the aminewith the phthalonitrile monomer.

EXAMPLE 60

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 38wt % of p-APB and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 150° C. prepared as in Example 11 was added1,4-bis(3-aminophenoxy)benzene (p-APB, 38 wt %) with stirring. Aftermixing, the dark curing mixture was cured by heating at 150° C. for 3hours. Gelation occurred during the heat treatment. A small sample (˜2mg) of this material was placed in a DSC pan. The DSC thermogram from25° to 400° C. showed endothermic transitions at 39° C. attributed tothe phthalonitrile monomer, at 119° C. and 146° C. attributed to thep-APB and an exothermic transition at 252° C. attributed to the reactionof the amine with the phthalonitrile monomer. After the sample wascooled, a second DSC thermogram was obtained from 25° C. to 270° C. Thesecond DSC thermogram showed no transitions. The lack of transitionsindicated that no further reaction of BAPS with the phthalonitrilemonomer had occurred.

EXAMPLE 61

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 38wt % of diphenylamine and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 150° C. prepared as in Example 11 was addeddiphenylamine (38 wt %) with stirring. After mixing, the dark curingmixture was cured by heating at 150° C. for 3 hours. Gelation occurredduring the heat treatment. A small sample (˜2 mg) of this material wasplaced in a DSC pan. The DSC thermogram from 25° to 400° C. showed anendothermic transition at 44° C. attributed to the phthalonitrilemonomer and an exothermic transition at 269° C. attributed to thereaction of the amine with the phthalonitrile monomer. After the samplewas cooled, a second DSC thermogram was obtained from 25° C. to 270° C.The second DSC thermogram showed no transitions. The lack of transitionsindicated that no further reaction of BAPS with the phthalonitrilemonomer had occurred.

EXAMPLE 62

Curing of phthalonitrile monomer (n=4) at 150° C in the presence of 38wt % of p-toluene sulfonic acid and DSC thermogram to 400° C.—To themelt of phthalonitrile monomer at 150° C. prepared as in Example 11 wasadded p-toluene sulfonic acid (38 wt %) with stirring. After mixing, thedark curing mixture was cured by heating at 150° C. for 3 hours.Gelation occurred during the heat treatment. A small sample (˜2 mg) ofthis material was placed in a DSC pan. The DSC thermogram from 25° to400° C. showed exothermic transitions at 248° C. and 296° C. attributedto the reaction of the amine with the phthalonitrile monomer. After thesample was cooled, a second DSC thermogram was obtained from 25° C. to270° C. The second DSC thermogram showed no transitions. The lack oftransitions indicated that no further reaction of BAPS with thephthalonitrile monomer had occurred.

EXAMPLE 63

DSC thermogram to 400° C. of phthalonitrile monomer (n=4) in thepresence of 59 wt % of cuprous bromide—A sample containing 1.4 mg of thephthalonitrile monomer prepared as in Example 15 and 2.0 mg (CuBr, 59 wt%) cuprous bromide was weighed into a DSC pan. The DSC thermogram from25° C. to 400° C. showed two endothermic transitions at 46° C. and at73° C. attributed to melting of the monomer and an exothermic transitionat 197° C. attributed to reaction of the metal salt with thephthalonitrile monomer. After the sample was cooled, a second DSCthermogram was obtained from 25° C. to 400° C. The second DSC thermogramshowed no transitions. The lack of transitions indicated that no furtherreaction of the metal salt with the phthalonitrile with the monomer hadoccurred.

EXAMPLE 64

Curing of phthalonitrile monomer (n=4) at 125° C. in the presence of 30wt % of cuprous iodide and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 125° C. prepared as in Example 15 was addedcuprous iodide (CuI, 30 wt %) with stirring. After mixing, the darkpolymerization mixture was cured by heating at 125° C. for 4 hours.Gelation occurred during the heat treatment. A small sample (˜2 mg) ofthis material was placed in a DSC pan. The DSC thermogram from 25° to400° C. showed endothermic transitions at 46° C. and at 73° C.attributed to the phthalonitrile monomer and a large exothermictransition at 258° C. attributed to the reaction of the metal salt withthe phthalonitrile monomer. After the sample was cooled, a second DSCthermogram was obtained from 25° C. to 270° C. The second DSC thermogramshowed only a small transition at 296° C. attributed to the reaction ofthe metal salt with the phthalonitrile monomer.

EXAMPLE 65

Curing of phthalonitrile monomer (n=4) at 125° C. in the presence of 30wt % of cuprous bromide and DSC thermogram to 400° C.—To the melt ofphthalonitrile monomer at 125° C. prepared as in Example 15 was addedcuprous bromide (CuBr, 30 wt %) with stirring. After mixing, the darkpolymerization mixture was cured by heating at 125° C. for 4 hours.Gelation occurred during the heat treatment. A small sample (˜2 mg) ofthis material was placed in a DSC pan. The DSC thermogram from 25° to400° C. showed an endothermic transition at 46° C. attributed to themetal salt and a large exothermic transition at 261° C. attributed tothe reaction of the metal salt with the phthalonitrile monomer. Afterthe sample was cooled, a second DSC thermogram was obtained from 25° C.to 270° C. The second DSC thermogram only a small transition at 265° C.attributed to the reaction of the metal salt with the phthalonitrilemonomer.

EXAMPLE 66

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 25wt % of stannous chloride dihydrate and DSC thermogram to 400° C.—To themelt of phthalonitrile monomer at 150° C. prepared as in Example 15 wasadded stannous chloride dihydrate (SnCl₂.2H₂O, 25 wt %) with stirring.After mixing, the dark polymerization mixture was cured by heating at150° C. for 18 hours. Gelation occurred during the heat treatment. Asmall sample (˜2 mg) of this material was placed in a DSC pan. The DSCthermogram from 25° to 400° C. showed endothermic transitions at 36° C.and at 60° C. attributed to the metal salt and the phthalonitrilemonomer, respectively, and an exothermic transition at 224° C.attributed to the reaction of the metal salt with the phthalonitrilemonomer. After the sample was cooled, a second DSC thermogram wasobtained from 25° C. to 400° C. The second DSC thermogram showed only asmall transition at 268° C. attributed to the reaction of the amine withthe phthalonitrile monomer.

EXAMPLE 67

Curing of phthalonitrile monomer (n=4) in the presence of 1.5 wt % ofstannous chloride dihydrate and the thermal stability of the curedpolymer—A sample containing 16.05 mg of the phthalonitrile monomerprepared as in Example 15 and 0.24 mg stannous chloride dihydrate(SnCl₂.2H₂O, 1.5 wt %) was weighed into a TGA pan. The mixture was curedby heating at 200° C. for 4 hours, 300° C. for 2 h and 375° C. for 8 hin a nitrogen atmosphere. The thermal stability of the cured polymer asdetermined by TGA was investigated by heating the cured samples from 25°C. to 1000° C. at 10° C./minute. The cured polymer commenced to loseweight slowly at ˜480° C. The high char yield of the cured polymer, 74%after heating to 1000° C., showed that the cured material had excellentthermal stability.

EXAMPLE 68

Curing of phthalonitrile monomer (n=4) in the presence of 2.4 wt % ofaluminum nitrate nonahydrate and the thermal stability of the curedpolymer—A sample containing 27.12 mg of the phthalonitrile monomerprepared as in Example 15 and 0.68 mg aluminum nitrate nonahydrate(Al(NO₃)₃.9H₂O, 2.4 wt %) was weighed into a TGA pan. The mixture wascured by heating at 200° C. for 4 hours, 300° C. for 2h and 375° C. for8 h in a nitrogen atmosphere. The thermal stability of the cured polymeras determined by TGA was investigated by heating the cured samples from25° C. to 1000° C. at 10° C./minute. The cured polymer commenced to loseweight slowly at ˜480° C. The high char yield of the cured polymer, 77%after heating to 1000° C., showed that the cured material had excellentthermal stability.

EXAMPLE 69

Curing of phthalonitrile monomer (n=4) in the presence of 1.0 wt % ofcuprous bromide and the thermal stability of the cured polymer—A samplecontaining 25.77 mg of the phthalonitrile monomer prepared as in Example15 and 0.25 mg cuprous bromide (CuBr, 1.0 wt %) were weighed into a TGApan. The mixture was cured by heating at 200° C. for 4 hours, 300° C.for 2 h and 375° C. for 8 h in a nitrogen atmosphere. The thermalstability of the cured polymer as determined by TGA was investigated byheating the cured samples from 25° C. to 1000° C. at 10° C./minute. Thecured polymer commenced to lose weight slowly at ˜480° C. The high charyield of the cured polymer, 73% after heating to 1000° C., showed thatthe cured material had excellent thermal stability.

EXAMPLE 70

Curing of phthalonitrile monomer (n=4) at 150° C. in the presence of 18wt % of aluminum nitrate nonahydrate and DSC thermogram to 400° C.—Asample containing 2.61 mg of the phthalonitrile monomer prepared as inExample 15 and 0.49 mg aluminum nitrate nonahydrate (Al(NO₃)₃.9H₂O, 16wt %) were weighed into a DSC pan. The DSC thermogram from 25° to 400°C. showed and two endothermic transitions at 48° C. and at 76° C.attributed to the phthalonitrile monomer and the metal salt,respectively, and an exothermic transition at 107° C. attributed to thereaction of the metal salt with the phthalonitrile monomer. After thesample was cooled, a second DSC thermogram was obtained from 25° C. to270° C. The second DSC thermogram showed no transitions. The lack oftransitions indicated that no further reaction of the metal salt withthe monomer had occurred.

EXAMPLE 71

DSC thermogram of phthalonitrile monomer (n=2) in the presence of 10 wt% cloisite 30A and DSC thermogram to 400° C.—To the phthalonitrilemonomer prepared as in Example 14 was added 10 wt % ternary ammoniumsalt of montmorillonite (available from Southern Clay Products, Inc.under the name Cloisite 30A) in a DSC pan. The DSC thermogram from 25°C. to 400° C. showed an endothermic transition at 51° C. attributed tomelting of the phthalonitrile monomer and an exothermic transition at296° C. attributed to reaction of the amine with the phthalonitrilemonomer.

1. An aryl-terminated aromatic ether oligomer comprising the formula:

wherein Ar is an independently selected divalent aromatic radical;wherein Ar′ is an independently selected monovalent aromatic radical;wherein n is an even integer greater than or equal to 2; and wherein nis not equal to 4 when every Ar is m-phenylene and every Ar′ is phenyl.2. The aryl-terminated aromatic ether oligomer of claim 1, wherein thearomatic ether oligomer comprises the formula:


3. A process of preparing an aryl-terminated aromatic ether oligomercomprising the formula:

wherein Ar is an independently selected divalent aromatic radical;wherein Ar′ is an independently selected monovalent aromatic radical;and wherein n is an even integer greater than or equal to 2; comprisingthe steps of: reacting a dihydroxyaromatic with a dihaloaromatic to forman aromatic ether oligomer; wherein either the dihydroxyaromatic or thedihaloaromatic is present in an excess amount; and wherein the reactionis performed in the presence of a copper compound and a base; andreacting the product of the previous step with either a haloaromatic ora hydroxyaromatic; wherein the haloaromatic is used if the previous stepused an excess of dihydroxyaromatic; and wherein the hydroxyaromatic isused if the previous step used an excess of dihaloaromatic.
 4. Theprocess of claim 3, wherein the copper compound is selected from thegroup consisting of CuI and CuBr.
 5. The process of claim 3, wherein thedihydroxyaromatic is present in an excess amount; and wherein thehaloaromatic is used.
 6. The process of claim 3, wherein thearyl-terminated aromatic ether oligomer formed by the process comprisesthe formula:


7. The process of claim 3, wherein the base is selected from the groupconsisting of cesium carbonate and potassium carbonate.